The outbreak of a mysterious disease which has claimed the lives of 56 children in Cambodia has prompted Vietnamese authorities to step up border checks and prevent the entry of animals and animal products.

The Vietnam Administration of Preventive Medicine on Tuesday ordered provinces bordering Cambodia to closely supervise the flow of travelers from Cambodia to Vietnam and tighten controls over the import of animals and animal products.

According to the World Health Organization, an unspecified illness striking children in Cambodia between April and July 8 has taken 56 lives among 74 infected cases.

The children are between three months and 11 years old, with the majority being under three years of age.

Fifty-nine cases, including the 56 fatal cases, had symptoms of high fever followed by rapid deterioration of respiratory functions.

Based on the latest laboratory results, a significant proportion of the samples tested positive for enterovirus 71 (EV-71), which causes the hand foot and mouth disease (HFMD). The EV-71 virus has been known to cause severe complications in some patients.

Additionally, a number of other pathogens, including dengue and streptococcus suis were identified in some of the samples. The samples were found to be negative for H5N1 and other influenza viruses, SARS and Nipah.

The Vietnam Administration of Preventive Medicine has asked directors of medical centers in border areas to implement quarantine procedures and other preventive measures.

Any traveler who shows symptoms of the disease must be quarantined, it said.

The department also asked authorities at border gates to tighten checks on animals and animal products, while preventive medicine centers near border gates are tasked with preparing medicines and chemicals for possible infected cases.

The HFMD is contagious and spreads through direct contact with the bodily fluids or feces of an infected person.

Last year, the disease claimed 169 lives of more than 110,000 infections in Vietnam.